An interlock mechanism as contemplated by the present invention is used in the drive line of a vehicle for releasably locking a driven member to a drive member. A specific example is a hub lock (interlock mechanism) for locking and unlocking a wheel hub (a driven member) to a wheel axle (a drive member).
U.S. Ser. No. 08/143,086 teaches an actuating mechanism for actuating a hub lock mechanism that is referred to as a pulse actuated interlock mechanism. The mechanism includes a piston and latch member that responds to a force, e.g., air pressure (negative or positive). The force moves the piston which moves a clutch ring to an interlocking relation with both the driven and drive members. The piston is latched to the latch member. The force is withdrawn whereas the piston is retained in the latched position. (The force which moves the piston to the latched position and is then withdrawn is here referred to as a first pulsating force.) A second pulsating force moves the piston relative to the latch member to release the latched engagement and the piston is returned to a withdrawn position. The clutch ring is moved to an engaged position and a disengaged position in response to unlatching and latching of the piston and latch member.
The latching mechanism relies on relative rotation of the piston and latch members to accomplish latching and unlatching of the piston. The latch member is a cam-like member rotatively fixed and provided on the inner wall of the housing for the interlock mechanism. Whereas the latching mechanism needs to be structured with precision, the component fixed to the inner wall of the housing is difficult to produce without incurring unduly expensive manufacturing processes. Failure to provide such precision affects reliability.